Conjunctival AL amyloidosis associated with a low-grade B-cell lymphoma.

A rare case of localized amyloidosis associated with a low-grade B-cell lymphoma involving the conjunctiva is described. Although infiltrating small lymphocytes and plasma cells showed little cytological atypia, molecular genetic examination revealed a prominent B-cell clonal immunoglobulin heavy chain (IgH) gene rearrangement in the tumor tissue. Immunoelectronmicroscopic examination showed immunoglobulin lambda light chain specificity in the amyloid deposit and Russell bodies in the surrounding plasma cells. We concluded that the immunoglobulin lambda light chain, produced by the tumor's differentiated plasma cells, is the precursor protein of the localized amyloidosis found in this case.